W-boson mass anomaly from a general SU(2)L scalar multiplet

We explain the W-boson mass anomaly by introducing an SU(2)_L scalar multiplet with general isospin and hypercharge {in the case without its vacuum expectation value}.It is shown that the dominant contribution from the scalar multiplet to the W-boson mass arises at the one-loop level,which can be expressed in terms of the electroweak (EW) oblique parameters T and S at leading order.We first rederive the general formulae of T and S induced by a scalar multiplet of EW charges,confirming ...     

A Model of Fermion Masses and Flavor Mixings with Family Symmetry SU(3)U(1)

The family symmetry SU(3)U(1) is proposed to solve flavor problems about fermion masses and flavor mixings.It is breaking is implemented by some flavon fields at the high-energy scale.In addition a discrete group Z 2 is introduced to generate tiny neutrino masses,which is broken by a real singlet scalar field at the middle-energy scale.The low-energy effective theory is elegantly obtained after all of super-heavy fermions are integrated out and decoupling.All the fermion mass matrices are regularly characterized by four fundamental matrices and thirteen parameters.The model can perfectly fit and account for all the current experimental data about the fermion masses and flavor mixings,in particular,it finely predicts the first generation quark masses and the values of θ l 13 and J l CP in neutrino physics.All of the results are promising to be tested in the future experiments.     

Room-temperature large photoinduced magnetoresistance in semi-insulating gallium arsenide-based device

It is still a great challenge for semiconductor based-devices to obtain a large magnetoresistance(MR) effect under a low magnetic field at room temperature. In this paper, the photoinduced MR effects under different intensities of illumination at room temperature are investigated in a semi-insulating gallium arsenide(SI-Ga As)-based Ag/SI–Ga As/Ag device. The device is subjected to the irradiation of light which is supplied by light-emitting diode(LED) lamp beads with a wavelength in a range of about 395 nm–405 nm and the working power of each LED lamp bead is about 33 mW. The photoinduced MR shows no saturation under magnetic fields(B) up to 1 T and the MR sensitivity S(S = MR/B) at low magnetic field(B = 0.001 T) can reach 15 T~(-1). It is found that the recombination of photoinduced electron and hole results in a positive photoinduced MR effect. This work implies that a high photoinduced S under a low magnetic field may be obtained in a non-magnetic semiconductor device with a very low intrinsic carrier concentration.     

Production of vector mesons in pentaquark state resonance channel in p-A ultraperipheral collisions

Ultraperipheral collisions(UPCs) of protons and nuclei are important for the study of the photoproduction of vector mesons and exotic states.The photoproduction of vector mesons in the pentaquark resonance channel in p-Au UPCs at the Relative Heavy Ion Collider(RHIC) and p-Pb UPCs at the Large Hadron Collider(LHC) is investigated by employing the STARlight package.The cross sections of vector mesons via the pentaquark state resonance channel are obtained using the effective Lagrangian method.The pseudo-rapidity and rapidity distributions of J/Ψ and γ(1 S) are given for p-Au UPCs at the RHIC and p-PbUPCs at the LHC.It is found that the RHIC is a better platform for discovering pentaquark states than the LHC.Moreover,Pb(11080) is easier to identify than PC(4312) because the background of γ(1 S) is weaker than that of J/Ψ in the t-channel at the RHIC.     

Mixed Symmetry States in Even—Even ^96—108Mo Nuclei

Excitation energies and electromagnetic transition strengths in even-even ^96-108Mo nuclei have been described systematically be using the proton-neutron interacting boson model (IBM-2).It appears that the properties of low-lying levels in these isotopes,for which the comparison between experiment and theory is possible,can be satisfactorily described by the IBM-2 model,provided proper account is taken of the presence at low energy of states having a mixed-symmetry character.It seems possible to identify,in each isotope,a few states having such a character,the lowest ones being either 22^ or 23^ levels.It is found that these nuclei are in the transition from U(5) to SU(3).     

Looking for new physics via semi-leptonic and leptonic rare decays of D and D_s

It is well recognized that looking for new physics at lower energy colliders is a path which is complementary to high energy machines such as the LHC.Using the large volume of data collected by BESIII,we may have a unique opportunity to tackle this.In this paper we calculate the branching ratios of the semi-leptonic processes D_s~+ →K~+e~-e~+ and D_s~+ →K~+e~-μ~+,and the leptonic processes D~0→ e~-e~+ and D~0→ e~-μ~+,in the frameworks of the U(1) model,2HDM and unparticle model.It is found that both the U(1) model and 2HDM may influence the semi-leptonic decay rates,but only the U(1) model offers substantial contributions to the pure leptonic decays,and the resultant branching ratio of D~0→e~-μ~+ can be as large as 10~(-7)~10~(-8).This might be observed at the future super τ-charm factory.     

Tunneling Negative Magnetoresistance via δ Doping in a Graphene-Based Magnetic Tunnel Junction

We investigate the tunneling magnetoresistance via S doping in a graphene-based magnetic tunnel junction in detail.It is found that the transmission probability and the conductance oscillates with the position and the aptitude of the 5 doping.Also,both the transmission probability and the conductance at the parallel configuration are suppressed by the magnetic field more obviously than that at the antiparallel configuration,which implies a large negative magnetoresistance for this device.The results show that the negative magnetoresistance of over 300% at B=1.0 T is observed by choosing suitable doped parameters,and the temperature plays an important role in the magnetoresistance.Thus it is possible to open a way to effectively manipulate the magnetoresistance devices,and to make a type of magnetoresistance device by controlling the structural parameter of the δ doping.     

Transverse mass distributions in central heavy-ion collisions at high energies

The transverse mass spectra of protons, pions, kaons, Lambda and Antilambda produced in central nucleus-nucleus collisions at high energies are described by using one-temperature and two-temperature emission pictures. The calculated results are compared and found to be in good agreement with the experimental data of the E895, E866 and E917 Collaborations measured in central Au-Au collisions at the Alternating Gradient Synchrotron (AGS) energies and the NA49 Collaboration measured in central Pb-Pb collisions at the Super Proton Synchrotron (SPS) energies. It is demonstrated that the transverse mass distributions of protons, kaons, Lambda and Antilambda, except for Lambda hyperons produced in central Pb-Pb collisions at 158 A GeV, can be described by using the one-temperature emission picture, and for pions, we need to use the two-temperature emission picture.     

热力学中之一问题(正误)

ERRATA It has been pointed out by Mr.S.C.Chen(陳世昌)in a private communicationthat the discussion of the case(c)in my paper with the above title is wrong.Since in the case(c)there is an irrevrsible flow of heat from the gas at the highertemperature to the one at the lower temperature,the total entropy cannot remainconstant as stated,but must have increased in the end of the process.As a con-sequence the formula(22)for the final pressure is wrong,and the whole discussionof the case(c)has to be rewritten.The following account appears,I believe,tobe correct.     

Chemical Instability in Heavy Ion Collisions at Intermediate Energies

With the establishment of secondary beam facilities at many laboratories around the world, one can investi-gate the properties of nuclei very far from the β stability line and isospin degrees of freedom in nuclear reactions at wide energy ranges. It is also possible to explore the chemical instability of hot and isospin-asymmetric nuclear matter. A better agreement with the experimental data has been found in our recent study by means of an isospin dependent quantum molecular dynamics (IQMD) mode. Recently experiments really reported the isospin dependence of multifragment production in reactions of ^58Fe ^58Fe and ^58Ni ^58Ni at higher incident energ.y; These phenomena may be related to the chemical instability in HIC induced by neutron-rich nuclei and therefore it is a challenge for theoretical and experimental nuclear physicists to investigate the chemical instability in heavv ion collisions.     

Production of hidden-charm and hidden-bottom pentaquark states in electron-proton collisions

Electro-production of several pentaquark states is investigated in this study.The eSTARlight package is adapted to study the electro-production of J/ψand γ(1S)via pentaquark P_cand P_bresonance channels in ep→eJ/ψp and ep→eγ(1S)p scattering processes at the proposed electron-ion colliders(EICs).The results obtained in this study are compared to those of non-resonance t-channels,which are described in the pomeron exchange model developed in our studies.Some pseudo-rapidity and rapidity distributions of J/ψand γ(1S)are presented for the proposed EICs,including EicC and EIC-US.It is found that EicC is a good platform to identify P_b states in the future.     

Pure spin polarized transport based on Rashba spin orbit interaction through the Aharonov Bohm interferometer embodied four-quantum-dot ring

The spin-polarized linear conductance spectrum and current-voltage characteristics in a four-quantum-dot ring embodied into Aharonov-Bohm (AB) interferometer are investigated theoretically by considering a local Rashba spin-orbit interaction. It shows that the spin-polarized linear conductance and the corresponding spin polarization are each a function of magnetic flux phase at zero bias voltage with a period of 2π, and that Hubbard U cannot influence the electron transport properties in this case. When adjusting appropriately the structural parameter of inter-dot coupling and dot-lead coupling strength, the electronic spin polarization can reach a maximum value. Furthermore, by adjusting the bias voltages applied to the leads, the spin-up and spin-down currents move in opposite directions and pure spin current exists in the configuration space in appropriate situations. Based on the numerical results, such a model can be applied to the design of a spin filter device.     

The 12th Western Pacific Acoustics Conference will be held in Singapore

<正>The 12th Western Pacific Acoustics Conference will be held at the Grand Copthorne Waterfront Hotel in Singapore from 6 to 10 December,2015.It is organized by the Society of Acoustics(Singapore)and supported by the Western Pacific Regional Commission for Acoustics,the National University of Singapore,the Nanyang Technological University and the Ocean Engineering Society,IEEE Singapore branch.The triennial WESPAC(Western Pacific Acoustics Conference)originated in Singapore in 1982,with the aim to promote communication and stimulate interactions in all aspects of acoustics in the region.The usual size of the conference is around 400 participants.Up to now,11 WESPAC conferences have been held successfully,of which 4 times in China.They     

Influence of Total Ionizing Dose Irradiation on Low-Frequency Noise Responses in Partially Depleted SOI nMOSFETs

Total ionizing dose effect induced low frequency degradations in 130 nm partially depleted silicon-on-insulator(SOI) technology are studied by ~(60) Co γ-ray irradiation. The experimental results show that the flicker noise at the front gate is not affected by the radiation since the radiation induced trapped charge in the thin gate oxide can be ignored. However, both the Lorenz spectrum noise, which is related to the linear kink effect(LKE) at the front gate, and the flicker noise at the back gate are sensitive to radiation. The radiation induced trapped charge in shallow trench isolation and the buried oxide can deplete the nearby body region and can activate the traps which reside in the depletion region. These traps act as a GR center and accelerate the consumption of the accumulated holes in the floating body.It results in the attenuation of the LKE and the increase of the Lorenz spectrum noise. Simultaneously, the radiation induced trapped charge in the buried oxide can directly lead to an enhanced flicker noise at the back gate. The trapped charge density in the buried oxide is extracted to increase from 2.21×10~(18)eV~(-1)cm~(-3) to 3.59×10~(18)eV~(-1)cm~(-3) after irradiation.     

K_2S-activated carbons developed from coal and their methane adsorption behaviors

The main purpose of this work is to prepare various activated carbons by K2S activation of coal with size fractions of 60-80 meshes, and investigate the microporosity development and corresponding methane storage capacities. Raw coal is mixed with K2S powder, and then heated at 750 ℃-900 ℃ for 30 min-150 min in N2 atmosphere to produce the adsorbents. The texture and surface morphology are characterized by a N2 adsorption/desorption isotherm at 77 K and scanning electron microscopy （SEM）. The chemical properties of carbons are confirmed by ultimate analysis. The crystal structure and degree of graphitization are tested by X-ray diffraction and Raman spectra. The relationship between sulfur content and the specific surface area of the adsorbents is also determined. K2S activation is helps to bring about better development of pore texture. These adsorbents are microporous materials with textural parameters increasing in a range of specific surface area 72.27 m2/g-657.7 m2/g and micropore volume 0.035 cm3/g-0.334 cm3/g. The ability of activated carbons to adsorb methane is measured at 298 K and at pressures up to 5.0 MPa by a volumetric method. The Langmuir model fits the experimental data well. It is concluded that the high specific surface area and micropore volume of activated carbons do determine methane adsorption capacity. The adsorbents obtained at 800 ℃ for 90 min with K2S/raw coal mass ratios of 1.0 and 1.2 show the highest methane adsorption capacities amounting to 106.98 mg/g and 106.17 mg/g, respectively.     

Molecular Dynamics Simulation of Xe Behavior in U-Mo Alloys Fuel

Classical molecular dynamics simulations are used to investigate the fission gas Xe behavior in a U-Mo alloy fuel matrix. The embedded atom method potential proposed by Smirnova et al. is used to describe the U-Mo-Xe system. The results show that the initial configuration of interstitial Xe atoms in U-Mo alloys is very instable and has a strong tendency to get together and to form a Xe bubble by ejecting the adjacent U atoms and Mo atoms from their former normal lattice sites. The pressure in Xe bubbles is initially quite high and then drops with increasing Xe concentration obviously. The matrix swelling of U-Mo alloys associated with the Xe bubble growth follows approximately a linear relationship with the ratio of Xe to U at low Xe concentration while the rate of swelling increases rapidly at high Xe concentration. The simulation results are in good agreement with the experimental data. The recovery of the damaged structure in the U-Mo alloys matrix is also investigated. It is shown that a damaged structure cannot be recovered completely after a system is relaxed for a long time while still having lots of defects.     

Event selection in CSR-ETF U+U collision

Uranium on uranium target (U+U) collision experiment has been proposed to be performed on Cooling Storage Ring (CSR), External Target Facility (ETF), which is to be built at Lanzhou, China, delivering the uranium beam up to 520 MeV/nucleon. It is predicted that the tip-tip U+U collision patterns can produce significant high baryon density and long duration nuclear matter to study the nuclear Equation of State (EoS). As the random orientation in U+U collisions, it is necessary to select the interested tip-tip events from the large trivia background. A Relativistic Transport (ART1.0) Model is applied to compute the random mini-biased U+U collisions to select our most favorable tip-tip events. It is found that applying various combination cut on the forward neutron multiplicity and forward charged particle multiplicity of the random U+U mini-biased sample, we can select the tip-tip configuration with certain purity and efficiency.     

LATTICE QUANTUM CHROMODYNAMICS

<正>Updated September 2013 by S.Hashimoto(KEK),J.Laiho(Syracuse University),and S.R.Sharpe(University of Washington).18.1.Lattice regularization of QCD Gauge theories form the building blocks of the Standard Model.While the SU(2)and U(l)parts have weak couplings and can be studied accurately with perturbative methods,the SU(3)component—QCD—is only amenable to a perturbative treatment at high energies.The growth of the coupling constant in the infrared—the flip-side of asymptotic freedom—requires the use of non-perturbative methods to determine the low energy properties of QCD.Lattice gauge theory,proposed by K.Wilson in 1974[1],provides such a method,for it gives a non-perturbative definition of vector-like gauge field theories like QCD.In lattice regularized QCD—commonly called lattice QCD or LQCD—Euclidean space-time is discretized,usually on a hypercubic     

Structural Characteristics of Cerium Oxide Nanocrystals Prepared by the Microemulsion Method

The aim of this work is to investigate the microstructure development of erium oxide nanocrystal,prepared by the microemulsion process,as a function of annealing temperature in air.Combined with the HRTEM and the thermogravimetric-differential thermal analysis in air.Combined withthe HRTEm and the thremogravimetric-differential thermal analysis(TG-DTA),the XRD patterns reveal that the sample annealed at 623 K is amorphous,and the formation of cerium oxide nanocrystal occurs above 773 K.The local structural and electronic properties in the nanocrystallization process are probed by X-ray absorption spectra (XAS) at the Ce L3 edge.It is found that the phase structure changes from triclinic to cubic (CeO2),and the electroic structure changes from Ce^3 to Ce^4 upon increasing the annealing temperature.     

Structural transitions in NaNH_2 via recrystallization under high pressure

Multiple phase transitions are detected in sodium amide(NaNH_2), an important hydrogen storage material, upon compression in diamond anvil cells(DAC) by using Raman spectroscopy and x-ray diffraction(XRD) measurements.Additional Bragg reflections appear on lower and higher angle sides of the original ones at ～1.07 GPa and 1.84 GPa,accompanied by obvious changes in Raman spectroscopy, respectively.It reveals that NaNH_2 undergoes the high-pressure phase sequence(α–β–γ) up to 20 GPa at room temperature.Spectral analysis indicates an orthorhombic structure with PBAN space group for the γ phase.We also experimentally observe high pressure induced recrystallization in alkaline amide compounds for the first time.